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Postcopulatory processes might play an important role in sexual selection. In theory, fertilization success could be controlled by females via selection of particular sperm within their reproductive tract, or it could be determined by sperm competition per se. In practice, these two mechanisms are difficult to disentangle. To assess the relative importance of both mechanisms we used artificial insemination in combination with measurements of sperm quality (swimming speed and motility) in mallards. In this species, females often lack behavioral control over copulations and hence may use postcopulatory mechanisms to optimize their reproductive output. One important factor affecting female fitness may be selection of genetically compatible males. To investigate the influence of sperm quality and parental relatedness on paternity we inseminated 12 groups of related females with a sperm mixture containing equal numbers of sperm from a brother and from an unrelated male. Paternity was independent of the relatedness of the siring male to the female but was significantly affected by long-term sperm swimming speed and motility. No interaction between relatedness and sperm quality on paternity was observed. These results suggest that female mallards are not able to select sperm on a purely genetic basis and emphasize the importance of sperm quality in gaining paternity. Copyright 2005.

The steroid hormone testosterone (T) mediates the expression of many secondary sexual characters, including behaviors which influence male reproductive success. Testes are one of the major sources of androgens, in particular of T. Although a positive relationship between testes size and T levels could be hypothesized, it has rarely been tested intraspecifically. We investigated this link in mallards (Anas platyrhynchos) using a double-antibody radioimmuno-assay to measure hormone levels and X-rays to determine testes size. Here, we report a positive correlation between both traits in a group of 13 drakes during the reproductive season.

Female mate choice is often based on exaggerated sexual traits, signals of male qualities that females cannot assess directly. Two such key qualities are male immune and/or sexual competence, whereby honesty in signalling could be maintained by physiological trade-offs. Carotenoid-based ornaments likely constitute such honest signals, as there is direct competition for (limited) carotenoids between ornament deposition and anti-oxidant support of immune or sperm functioning. Using spectrometry, we assessed the potential signalling function of the yellow, carotenoid-based colour of the bill of male mallards, a target of female mate choice. Here we demonstrate that bill reflectance varied with plasma carotenoid level, indicating antioxidant reserves. Moreover, lower relative UV reflectance during autumn pairing predicted immune responsiveness and correlated positively with sperm velocity during breeding, a trait that affects fertility. Our data provide support for current theories that females could use carotenoid-based sexual signals to detect immune vigour and fertilizing ability of prospective mates.

The transient simulation of noise in electronic circuits leads to differential-algebraic equations, additively disturbed by white noise. For these systems, we present a mathematical model based on the theory of stochastic differential equations, along with an implicit two-step method for their numerical treatment. This numerical scheme works directly on the given structure of the equations which makes very efficient implementations possible. The order of convergence is preserved. The theoretical results are verified by numerical noise simulations of benchmark circuits.

Due to the continuing miniaturization process of electronic integrated circuits the modeling has to take additional effects like noise into account. Adding the noise sources to the model of an electronic circuit yields stochastic differential equations (SDEs). The simulation of such equations leads to new difficulties like numerical problems and efficiency issues. In this paper we present the modeling and simulation of an inverter circuit. In addition, a modified Adams scheme is presented which allows the efficient numerical solution for SDEs with additive noise.

A new numerical integration scheme for the simulation of differential-algebraic equations is presented. In the context of the computer-aided design of electronic circuits, the modeling of highly oscillatory circuits leads to oscillatory differential-algebraic equations. Standard schemes can solve these equations neither efficiently nor reliably. To overcome the problems of classical numerical methods, the new discretization scheme is based on the principle of coherence due to Hersch in combination with a multistep approach. A Fortran77 implementation of the presented integration scheme reduces the simulation time for a quartz-controlled oscillator to about 2% compared with standard methods. Theretore, it is a useful tool for the design of highly oscillatory circuits.

The application of Adams methods for the numerical solution of stochastic differential equations is considered. Especially we discuss the path-wise (strong) solutions of stochastic differential equations with additive noise and their numerical computation. The special structure of these problems suggests the application of Adams methods, which are used for deterministic differential equations very successfully. Applications to circuit simulation are presented.

We show how charge distribution effects in MOS transistors are reflected only correctly by models based on the physical properties of the device. Hence one has to consider carefully the impact of modelling to obtain correct results for MOS circuits by numerical simulation. Additionally, the choice of an appropriate integration scheme is essential for both reliable and efficient simulation results. To spotlight these influences, we use a charge pump as an instructive test circuit and discuss a variety of modelling approaches.

Seven polymorphic microsatellite loci for paternity assessment in the mallard (Anas platyrhynchos)

This paper presents a new discretization scheme for the efficient integration of highly oscillatory second-order ordinary differential equations. The discretization scheme is based on the principle of coherence proposed by Hersch. The analysis of the formulas reveals properties such as absolute stability and P-stability which indicate the ability of the method to handle highly oscillatory differential equations. This is confirmed by numerical results.

Female mate choice is often based on exaggerated sexual traits, signals of male qualities that females cannot assess directly. Two such key qualities are male immune and/or sexual competence, whereby honesty in signalling could be maintained by physiological trade-offs. Carotenoid-based ornaments likely constitute such honest signals, as there is direct competition for (limited) carotenoids between ornament deposition and anti-oxidant support of immune or sperm functioning. Using spectrometry, we assessed the potential signalling function of the yellow, carotenoid-based colour of the bill of male mallards, a target of female mate choice. Here we demonstrate that bill reflectance varied with plasma carotenoid level, indicating antioxidant reserves. Moreover, lower relative UV reflectance during autumn pairing predicted immune responsiveness and correlated positively with sperm velocity during breeding, a trait that affects fertility. Our data provide support for current theories that females could use carotenoid-based sexual signals to detect immune vigour and fertilizing ability of prospective mates.

Evidence for extensive interspecific hybridization among species of the genus Daphnia has been accumulating on a global scale. Although there is evidence for limited gene flow between taxa via hybridization, many species still maintain discrete morphological and molecular characteristics. We studied temporal and spatial patterns of sexual reproduction within the Daphnia galeata‐hyalina‐ cucullata hybrid species complex in a lake (Plussee), located in northern Germany. Allozyme electrophoresis allowed us to track seasonal changes in taxon composition as well as the quantification of backcrosses. Sexually-reproducing animals (ephippial females and males) were mainly found in autumn.

Allocation trade-offs between the immune system and sexual traits are central to current sexual selection hypotheses but remain contentious. Such trade-offs could be brought about by the dual action of testosterone that stimulates sexual signals but also suppresses immune functions and/or by competition for carotenoids that can be deposited in ornaments or used as antioxidants in support of immune functions. We investigated the trade-off between investment in immunity and maintenance of testosterone, carotenoids, and sexually selected, carotenoid-based bill color in male mallards. Following a nonpathogenic immune challenge, facultative immune investment resulted in a syndrome of changes in allocation. Plasma carotenoids disappeared from circulation proportional to antibody production. In addition, the reflectance spectrum of the bill was affected; greater antibody production was associated with an increase in relative UV reflectance. Although changes in bill reflectance and plasma carotenoids were related, the relationship appeared more complex than direct competition with immunity. Finally, maintenance of testosterone was affected by immune investment: testosterone levels declined substantially when males produced more antibodies. Because males with high testosterone are preferred by females, the decline in testosterone, in addition to carotenoid depletion and effects on bill reflectance, could constitute a significant cost of immune investment.

Circuit simulation is one of the most important steps during the development of electronic circuits. A standard task for circuit simulation is the transient analysis, the simulation of the chip on transistor level in the time domain. Normally, this simulation does not include noise source. As the supply voltage decreases, the signal-to-noise ratio also decreases and noise effects become more and more important. In this paper the modeling of noise in the time-domain will be described. Especially for flicker noise, new and efficient approaches are presented. For a numerical treatment of the resulting stochastic differential-algebraic equations, a new numerical scheme is given for the charge-oriented formulation of the circuit equations. Finally, the results of numerical experiments are presented

A new numerical integration scheme for the simulation of stochastic differential equations is presented. In the context of the computer-aided design of electronic circuits, the modeling of circuits under the influence of electronic noise leads to stochastic differential equations. The available schemes can not solve these equations efficiently. The new discretiziation scheme is constructed similar to multistep schemes for ordinary differential equations. A Fortran77 implementation of the presented integration scheme reduces the simulation time for a ring oscillator to about 17.5% compared with common methods. Therefore, it is an efficient tool for the design of noisy circuits.

Background: While inverted nipples are a common problem, mammary fistulas are very rare. A mammary duct ectasia is both consequence of and reason for a nipple retraction.

Kaolin reagiert mit konzentrierter siedender Natronlauge bei Gegenwart von Calcium- oder Bariumverbindungen unter Bildung schwer loslicher Silicate und von loslichem Natriumaluminat. Reaction of Kaoline with Alkali Hydroxides in Presence of the Compounds of Alkali and Alkaline Earth Metals Kaoline forms in presence of calcium or bariumcompounds with concentrated boiling sodium hydroxide solutions nearly insoluble silicates and soluble natrium aluminate.

A detoxification regimen has been found to be safe for use by individuals exposed to recreational (abused) and medical drugs, patent medicines, occupational and environmental chemicals. Patients with high blood pressure had a mean reduction of 30.8 mm systolic, 23.3 mm diastolic. Cholesterol level mean reduction was 19.5 mg/100ml, while triglycerides did not change. Medical complications associated with the program were rare, occurring in less than three percent of the subjects. The program resulted in improvements in psychological test scores. The mean increase in Wechsler Adult Intelligence Scale IQ was 6.7 points. High Minnesota Multiphasic Personality Inventory profiles decreased on the third scale (10.7), the fourth scale (8.0), the fifth scale (4.5) and the sixth scale (8.0). The decrease in the fourth scale suggests hope for sociopaths, a group with fourth scale scores not improved by National Institute for Mental Health or Narcotic Addict Rehabilitation Act inpatient programs.

Synthesis of bidentate pyridylazo reagents and the spectrophotometric determination of copper in a flow-injection system. K. Ohshita, H. Wada and G. Nakagawa. In der Absicht, ein geeignetes Reagens fiir die spektralphotometrische Bestimmung von Kupfer(II) zu finden, wurden einige Pyridylazound Thiazolylazoverbindungen synthetisiert. Unter diesen zeigte das wasser16sliche zweizfihnihge 4-(3,5-Dibrom-2-pyridylazo)-N-ethyl-N-(3-sulfopropyl)anilin die analytisch gfinstigsten Eigenschaften, vor allem die h6chste Empfindlichkeit (z = 1,24 x 105 1 m o l % m l bei 638 nm). In Gegenwart yon Natriumdodecylsulfat bildet sich ein st6chiometrischer 1:2 Cu:L-Komplex. In cinem entsprechend ausgelegten FlieBinjektionssystem k6nnen 60 Proben/h mit einer Cu(II)-Konzentration von 10-200 gg/1 bestimmt werden. Die L~inge der Mischspirale (Teflon, 0,5 mm) betr[igt 200 cm, die Fliel3geschwindigkeiten sind auf I ml/ rain eingestellt, die DurchfluBzelle von 20 pl hat eine optische Wegl/inge yon 10 mm. Als Tr/igerl6sung verwendet man Acetatpuffer pH 4,5, die Konzentrationen von Reagensund SDS-L6sung betragen 4 x 10-5 M bzw. 0,4%. Linearit/itsbereich der Eichkurve: 20-200 gg Cu(II)/1. Das Verfahren kann zur Cu-Bestimmung in Blutserum (enteiweil3t) eingesetzt werden. Anal. Chim. Aeta 176, 4 1 5 0 (1985). Lab. Chem., Daido Inst. Chem., Minami-ku, Nagoya (J) W. Czysz